USB Question

[[AK]Leonidas]

My daughter's computer has had some weird USB problems lately. She has five USB devices: mouse, printer, drawing tablet, scanner, and web camera. To help her run these she has a USB hub that plugs into one of the two USB ports on her computer and creates four new USB sockets. So between the remaining USB socket on her computer and the four from the hub, she's just covered for her five devices.

But these devices are not happy campers, especially the printer. When she first set up the system, the printer worked fine. But when she plugged in all the USB devices, the printer stopped working. Then we plugged the printer directly into the computer's USB port and unplugged some less essential devices, and the printer started working. Except now every time she prints, the USB mouse quits working. The goal here is to get all five devices working at the same time, so she doesn't have to constantly unplug and replug things.

Is this a simple power problem? Maybe the USB devices demand more power for data transmission than my computer and hub can provide. If so, I'll get her a second hub with its own power source, and that should fix it.

Or is this a software-side problem? She's got a VIA mobo with the latest 4-in-1 driver, so I don't know how else to jiggle things on the software side. Despite the advertising on the capabilities of USB, is there a practical limit on how many USB devices the driver or OS can handle?

[Dr_K]

Leo, how large is your daughters power supply? Is the port expander a powered one or not (I got the impression it's not)? Some device draw power directly from the usb ports, others have their own power supplies but can still draw some power from the port. With that many devices you may be over whelming the ports power limits. If I remember correctly, the usb can theoretically handle 255 devices but there may be some practical limitations to that.

Also make sure she has the most up to date drivers for each device. Is she running Win98, ME or 2000 or XP?

[[AK]Leonidas]

The USB hub has its own power supply. I'm not sure of the wattage in the computer itself. USB hubs are pretty cheap, so I'll probably just get her one for Xmas. I'm just hoping that will fix it.

Her box is running Win 98. The VIA motherboard drivers are the only ones I know for her system. I'm pretty sure that the mobo is all VIA, though I'm not sure how I would check.

If it helps, she's already figured out that once the mouse freezes after the printer's been used, all she has to do it unplug and replug the mouse.

[Dr_K]

Sounds more like a driver conflict between the mouse and the printer. Check for updated mouse and printer drivers if they aren't current. Microsoft for the most recent Win98 USB interface drivers. Beyond that, I'm not sure. If the USB Hub has it's own power supply, then there shouldn't be a problem there.


This may or may not be of help:

http://www.microsoft.com/downloads/r...arch&ordinal=7